嘉善前体物与气象因子对臭氧生成的影响及臭氧潜在源区分析

利用2017年嘉善善西超级站臭氧（O₃）及其前体物（NO_x和VOCs）以及气象因子（温度、湿度、风速）逐小时数据，分析了2017年全年NO_x和O₃的变化特征以及春季（4—5月）、夏季（7—8月）NO_x和气象因子对O₃生成的影响，利用O₃生成潜势（OFP）评估了VOCs大气化学反应活性，并通过潜在源区贡献（PSCF）和浓度权重轨迹（CWT）方法分析了嘉善春、夏季O₃潜在源区贡献特征。研究发现：O₃日变化特征为单峰结构，NO_x为弱双峰结构。O₃浓度在3—9月较高，春、夏季O₃浓度峰值分别出现在15：00和14：00，春、夏季的NO_x、O₃日变化与2017年全年日变化趋势基本一致。NO_x对O₃存在滴定作用，且低湿高温有利于O₃浓度的升高。春、夏季O₃生成潜势贡献均表现为烯烃 > 芳香烃 > 烷烃，由于烯烃光化学活性较高，夏季烯烃浓度升高导致其贡献较春季增长约18.1个百分点，且夏季VOCs平均最大O₃增量反应活性高于春季。PSCF和CWT分析结果表明，嘉善春季的潜在源区主要为本地、西南方向和东南方向，夏季的潜在源区主要为本地、西北方向、西南方向以及东南方向。

Impacts of Precursors and Meteorological Factors on Ozone Pollution and Its Potential Sources in Jiashan

Based on the hourly data of ozone precursors (NO_x and VOCs),ozone (O₃) and meteorology (temperature,humidity,wind speed) at Shanxi Super Station in 2017,the variation characteristics of NO_x and O₃ in the whole year of 2017 and the effects of NO_x and meteorological elements on the formation of O₃ in spring and summer were analyzed,the atmospheric chemical reactivity of VOCs was evaluated using OzoneFormation Potential (OFP),and Potential Source Contribution Function (PSCF) and Concentration-Weighted Trajectory (CWT) methods combined with weight factors were applied to study the potential source regions of O₃.It was found that the diurnal variation of O₃ was single-peak distribution,and the diurnal variation of NO_x was weak bimodal structure.The concentration of O₃ was higher from March to September,and the peak of O₃ in spring (from April to May) and summer (from July to August) occured at 15:00 and 14:00 respectively.The diurnal variation trend of NO_x and O₃ in spring and summer was basically consistent with that of the whole year in 2017.The higher the concentration of NO_x,the more inhibited the formation of ozone,and low humidity and high temperature were beneficial to the increase of ozone concentration.The contribution of OFP in spring and summer appeared as olefin > aromatics > alkanes.The olefin photochemical activity was relatively high,which contribution increased about 18.1 percentage points in summer.PSCF and CWT analysis showed that the potential sources of Jiashan in spring were mainly local,southwest and southeast,and in summer,the potential sources mainly were local,northwest,southwest and southeast.